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BP: Fachverband Biologische Physik

BP 6: Posters: DNA and DNA Enzymes

BP 6.3: Poster

Montag, 22. März 2010, 17:15–20:00, Poster B1

High resolution optical tweezers for study of eukaryotic transcription — •Noemi Maria Porcellato, Adam Muschielok, and Jens Michaelis — Dep. für Chemie und Biochemie LMU München, Munich, Germany

For the single-molecule analysis of enzymes moving on DNA, for instance eukaryotic RNA polymerase II (Pol II), we have built a high resolution dual-trap optical tweezers apparatus. The main aim is to achieve very high spatial resolution (down to the level of single basepairs) and low drift. Since both traps are created by the same laser and the optical path where the beams are separated is minimized, drift is essentially eliminated. Together with sound isolation and enclosure of the instrument we achieve high spatial resolution shown in test experiments with DNA tethers. In order to efficiently load beads into the traps and to control buffer conditions during the experiments we use a custom built 5 channel microfluidic flow system. We discuss general design considerations, show calibration of the trap stiffness, first test measurements and preliminary Pol II transcription data.